B. Goldstein

Exploding-Wire Photon Testing of Skynet Satellite

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SGEMP Response Investigation with Exploding-Wire Photons, Part II

The results of SGEMP experiments and calculations on simple objects with an exploding wire source were reported in Reference 1. In Reference 1 the comparisons between data and experiment suggested a number of discrepancies. Further analysis of the data together with additional calculations has resolved or mitigated many of these discrepancies. The experiments represent an important step in the understanding, simulation and verification of SGEMP phenomenology and this paper presents the newest developments in the analysis.

Satellite SGEMP Simulation Fidelity Criteria

In order to simulate the effects of an exoatmospheric nuclear environment in a laboratory, a number of compromises must be made. The extent to which these compromises modify the numerical values of the important parameters to be simulated reflects upon the simulation quality of the experiment. The concept of simulation fidelity is necessary for interpreting test results and useful in designing simulators. An SGEMP simulator, for example, may not have the same X-ray spectrum, time history or electromagnetic boundaries as does the real threat circumstances. The purpose of this paper is to present a methodology for quantifying the concept of simulation fidelity, explain the reasoning underlying the methodology and apply the methodology to one specific problem, vacuum tank wall perturbations in the SXTF SGEMP simulator.

Three-Dimensional SGEMP Simulation of an Idealized Fltsatcom in SXTF

An investigation is made of tank physics issues which affect simulator fidelity of the baseline SXTF design. Detailed, three-dimensional calculations are made out to 500 nsec using the Cartesian SOS code. The first calculation considers the SGEMP response of an idealized FLTSATCOM geometry in the cylindrical SXTF simulator. The second considers the response of the identical satellite in a free-space environment. A comparison of calculated satellite responses demonstrates that, for the configuration studied, the cylindrical SXTF simulator provides a good approximation to the free-space environment. Similar results were previously obtained for a spherical simulator geometry.

Potential of an Insulating Disk Irradiated by an Electron Beam

Thin insulating films on satellites are known to charge to kilovolt potentials in space due to irradiation by charged particles. The electrostatic fields which develop on their surface are shown to be governed by emission limited charging. It is unnecessary to consider surface or bulk conductivity to explain the charging of the two-dimensional surfaces except, perhaps, extremely close to the edge of the dielectric.

Satellite Response and Separate Body Testing within an SGEMP Simulator

A study is made of the feasibility of separate body testing of satellites within SGEMP simulators. A method is suggested which reproduces the two lowest frequency satellite modes of a triaxial satellite using a lumped circuit parameter model. A systematic numerical study of lumped circuit parameter models of triaxial satellite systems is also presented.

On the Simulation Fidelity Requirements for Vacuum Tank and Low Frequency Spacecraft Mode Damping in an SGEMP Simulator

This paper analytically examines the electromagnetic response of a satellite system in an SGEMP simulator vacuum tank. Both higher frequency tank modes and lower frequency system modes are considered. It is shown, for a spherical satellite in a spherical tank, that strong damping of tank modes brings the frequency response in the tank toward coincidence with the free space frequency response. It is also shown that higher resistances are required to optimally damp the lower frequency satellite modes than are necessary to optimally damp tank modes.

Avalanching in a One-Dimensional Diode

The role of avalanching in a low air pressure diode has been analyzed. The regime which was treated is characterized by an electron swarm having a temperature of less than a few electron volts.